Rocker arm guide member

ABSTRACT

An overhead camshaft internal combustion engine cylinder has a plurality of inlet valves and an exhaust valve, the rocker arms of some of which are inclined or canted to the vertical; a plate is provided that cooperates with the rocker arm to assure that the rocker arm moves pivotally in a vertical direction.

1,500,619 7/1924 llill...

United States Patent [72] Inventor Gray E.D. Ross Stock, lngatcstone,England [21 Appl. No. 778,434

[22] Filed Nov. 25, 1968 [45] Patented Feb. 16, 1971 [73] Assignee FordMotor Company Dearborn, Mich.

[32] Priority Feb. 1, 1968 [33] Great Britain [54] ROCKER ARM GUIDEMEMBER 7 Claims, 1 Drawing Fig. [52] U.S. Cl 123/9042, 123/193,123/9027, 123/9043, 123/9044 [5l] Int. Cl F0ll 1/18 [50] Field of Search123/90, l9l-0, 193, l93-H, 75-B, l95

[56] References Cited UNITED STATES PATENTS 1,915,237 6/1933 Moore123/191(O) 2,804,862 9/1957 Nedwidek l23/75(B) 2,902,014 9/1959 Leach123/90(1'1) 3,094,977 6/1963 Sampietro 123/90(1-1)X. 3,112,740 12/1963Sampietro l23/90(l-l) 3,166,058 1/1965 Zink 123/90(H4) 3,270,727 9/1966Nance 123/9001) 3,352,293 11/1967 Hulten.... 123/195X 3,401,678 9/1968Rose 123/90(H) 3,430,614 3/1969 Meacham 123/193(H)X FOREIGN PATENTS866,872 5/1961 Great Britain 123/90(H) Primary Examiner-A1 LawrenceSmith Attorneys-John R. Faulkner and Robert E. McCollum ABSTRACT: Anoverhead camshaft internal combustion engine cylinder has a plurality ofinlet valves and an exhaust valve, the rocker arms of some of which areinclined or canted to the vertical; a plate is provided that cooperateswith the rocker arm to assure that the rocker arm moves pivotally in avertical direction.

Pmmd Feb.-16, 1971 INVENTOR. GRAY E. D. ROSS ATTORNEY ROCKER ARM GUIDEMEMBER This invention relates to overhead camshaft internal combustionengines.

in many high performance engines, it is necessary to fit three valves toeach cylinder. This is difficult to achieve from a space standpoint ifthe planes containing the valve rocker arms are perpendicular to theline joining the axes of the cylinders. It is, therefore, not unusualfor the rocker arms to be inclined to the perpendicular to the linejoining the axes. Such rocker arms are known as oblique".

Oblique rocker arms have hitherto been invariably mounted on a rockerarm shaft. This, in the case of overhead camshaft engines, has resultedin difficulties in adjusting the valve clearances. Valve clearances canbe adjusted more simply in overhead camshaft engines if the rocker armsare individually stud mounted, i.e.,each pivotally mounted on a post,since the valve adjustment is effected merely by screwing the postfurther in or out of the cylinder head.

lt has'h itherto been impossible to combine in the same engine anoverhead camshaft and oblique or inclined rocker arms which are studmounted or mounted on posts because the overhead camshaft cams tend torock the rocker arms on the posts about the axes of the posts.

This invention enables oblique stud-mounted rocker arms to be fitted inoverhead camshaft engines. One end of each of a plurality of valverocker arms has a part-spherical socket that seats on the part-sphericalhead of a stud fixed in the cylinder head; the opposite end of each ofthe rocker arms engages the end of a valve stem; an overhead camshaftengages the top of the rocker arms between the studs "and valves; thestuds and valves are so located that at least some of the rocker armsare inclined to the perpendicular to the axis of the camshaft; and, amember rigid with the cylinder head engages the rocker arms between thestuds and valves to limit rotation of the rocker arms about the axes ofthe studs.

The invention is hereinafter particularly described with reference tothe accompanying drawing, which is a perspective view of part of thecylinder head of an internal combustion engine.

The figure shows a cylinder head that would be secured by bolts or othersuitable means (not shown) to a cylinder block having a bank of in-linecylinders. For clarity, only one is shown. Each cylinder has a pair ofinlet valves indicated by valve stems 3 and 5 and an exhaust valveindicated by a stem 7. The valves themselves are each conventional andare biased in the conventional manner to their closed positions bysprings 8.

Studs 9, 11, and 13 are threaded at one end, and screwed into aperturesin bosses extending from the head, as shown. Each serves as a post formounting one end of one of the rocker arms. The upper end of each of thestuds is formed as a part spherical bearing surface, and the studs canbe locked in adjusted position by nuts 15. For clarity, only the rockerarm 16 associated with inlet valve stem 5 will be shown and described.The others are of a similar construction.

Rocker arm 16 has at one end a part spherical concave surface 17 thatseats on its respective convex-ended stud 13. The opposite end of therocker arm engages'the valve stem 5. The central part of rocker arm 16has on its upper surface an arcuate wear portion 18 that is adapted tobe engaged by a cam not shown) fixed on a conventional overhead camshaft(not shown). The camshaft is rotatably mounted on a journal 19 in alower half bearing portion 20 supported on a platform 21. Thus, as thecamshaft rotates, the rocker arm 16 pivots about stud 13.

The planes of the three rocker arms are not all perpendicular to theaxis of the camshaft, but are inclined or at an oblique attitude. Thecanting of the rocker arms enables not only three valves but also largervalves to be used for each cylinder. However, since the cams do notexert a force perpendicular to the wear portions 18, a side force isexerted tending to rock the rocker arm 16 laterally about the axes ofthe stud 13. This is undesirable and is prevented by the inclusion of aguide member 22 that is fixed to the cylinder head and engages therocker arms at a point between the studs and valves. There is a separatemember 22 for each cylinder.

More specifically, the cylinder head has spaced along its length theintegral camshaft bearing supporting platforms 2]. Each side of eachplatform is formed with a central slot 23 that is parallel to the planein which the longitudinal axis of the cylinder bank lies. Each guidemember 22 is a vertically disposed plate that at each end is splithorizontally into two pieces. An upper offset or laterally bent tab part24 is joined to a lower part 25 that is offset or bent laterally in theopposite direction and fits into the slot 23. The upper surface of thelower offset part 25 lies in the same plane as the lower surface of theupper offset part 24. The lower surface of the upper offset part 24rests on the platform 21. The upper and lower offset parts at theopposite end of guide member 22 are bent in the same manner.

Lower camshaft bearings 20 (only one shown) seat on the platforms 21 andare secured thereto by bolts (not shown) extending through bores in thebearings to screw into the threaded apertures 26.

The lower camshaft bearings 20 have slots 27 in which the upper offsetparts 24 fit. The slots 27 are parallel to but offset laterally andvertically from slots 23 in platform 21. The lower bearings 20 engagethe upper surface of the lower offset parts 25, and thus prevent upwardmovement of the member 22. Downward movement of the member 22 isprevented by the lower surfaces of the upper offset parts 24 engagingthe platform 21. Longitudinal movement of the member 22 is prevented bythe member 22 engaging the bases of the slots in the platform and lowerbearing.

The plate 22 has a slot 28 for guidance of each of the three rockerarms, and the rocker arms are each provided with side bearing portions29 slidable in slot 28. The sides of the rocker arms 16 thus engage thesides of the slots 28, which prevents the rocker arms from pivotinglaterally around the vertical axis of stud 13.

Valve clearances can be adjusted simply by screwing the studs 9, 11 or13 in or out after the lock nuts have been slackened off.

There is a similarly arranged member 17 for each cylinder.

While the invention has been shown and described in its preferredembodiment, it will be clear to those skilled in the arts to which theinvention pertains that many changes and modifications may be madethereto without departing from the scope of the invention.

lclaim:

1. A valve train assembly for use in an internal combustion engine ofthe single overhead camshaft type having a plurality of inlet valves andan outlet valve for each cylinder, including a plurality of rocker armseach pivotally mounted at one end on a post adjustably secured in thecylinder head of said engine and engageable at the opposite end with thestem of one of said valves, said rocker arms each having means betweensaid post and valve stem adapted to be engageable by a cam on saidcamshaft for oscillating motion in a generally vertical direction aboutsaid post, the planes containing said rocker arms being nonparallel withrespect to each other whereby cam forces exert a side loading on said]rocker arms, and plate means operably secured to said head and havingmeans thereon cooperating with means on each of said rocker arms forguiding said rocker arm for oscillation in a vertical direction.

2. An assembly as in claim 1, said] plate means having a number of slotstherein, said rocker arms each having means slidably engageable with andaligned with said slots.

3. An assembly as in claim 1, the operable securing of said plate meansto said head including laterally offset portions of said plateengageable with movement restricting portions of said head.

4. An assembly as in claim 3, one of said offset portions beingengageable in slots in said head for preventing lateral relativemovement between said plate and head.

7. An assembly as in claim 1, said plate means at each end having anupper and a lower tab portion projecting laterally from said plateto'opposite sides thereof, said lower tab portion being engageable inslot means in said head to prevent longitudinal and lateral displacementtherefrom and vertical displacement in one direction, and said upper tabportion being engageable with a portion of said head to prevent verticalmovement of said plate in the opposite direction.

1. A valve train assembly for use in an internal combustion engine ofthe single overhead camshaft type having a plurality of inlet valves andan outlet valve for each cylinder, including a plurality of rocker armseach pivotally mounted at one end on a post adjustably secured in thecylinder head of said engine and engageable at the opposite end with thestem of one of said valves, said rocker arms each having means betweensaid post and valve stem adapted to be engageable by a cam on saidcamshaft for oscillating motion in a generally vertical direction aboutsaid post, the planes containing said rocker arms being nonparallel withrespect to each other whereby cam forces exert a side loading on saidrocker arms, and plate means operably secured to said head and havingmeans thereon cooperating with means on each of said rocker arms forguiding said rocker arm for oscillation in a vertical direction.
 2. Anassembly as in claim 1, said plate means having a number of slotstherein, said rocker arms each having means slidably engageable with andaligned with said slots.
 3. An assembly as in claim 1, the operablesecuring of said plate means to said head including laterally offsetportions of said plate engageable with movement restricting portions ofsaid head.
 4. An assembly as in claim 3, one of said offset portionsbeing engageable in slots in said head for preventing lateral relativemovement between said plate and head.
 5. An assembly as in claim 3, oneof said offset portions being engageable with means on said headrestricting vertical relative movement therebetween.
 6. An assembly asin claim 3, said movement restricting portions including meansengageable with one of said offset portions preventing relative movementbetween said head and plate in one vertical direction, and includingmeans engageable with another of said offset portions to preventrelative vertical movement between said head and plate in the otherdirection, said means including slotted and shouldered parts.
 7. Anassembly as in claim 1, said plate means at each end having an upper anda lower tab portion projecting laterally from said plate to oppositesides thereof, said lower tab portion being engageable in slot means insaid head to prevent longitudinal and lateral displacement therefrom andvertical displacement in one direction, and said upper tab portion beingengageable with a portion of said head to prevent vertical movement ofsaid plate in the opposite direction.